Butte County and Fresno County Sheriff officers remove the remains of a victim of the Camp Fire in Magalia, California. Bloomberg

Burned-out vehicles stand in Paradise, California. Bloomberg

Firefighters search a burned-out building in Paradise, California. Bloomberg

A Camp Fire evacuee watches television while camping in a Walmart Inc. store parking lot in Chico, California. Bloomberg

A Camp Fire evacuee plays with an abandoned dog in Chico, California. Bloomberg

The number of people missing in one of California's deadliest wildfires has soared to more than 600 as rescuers found the remains of another seven victims.

Authorities said the list of missing people jumped from 300 to 631 on Thursday as investigators went back and reviewed emergency calls made when the so-called Camp Fire in northern California erupted on November 8.

"I want you to understand that the chaos we were dealing with was extraordinary" when the fire broke out, Butte County Sheriff Kory Honea said, in explaining the surge in the number of people missing.

The seven additional victims raised the death toll from the Camp Fire to 63.

At least three other people died in southern California in another blaze dubbed the Woolsey Fire, which engulfed parts of Malibu, destroying the homes of several celebrities.

President Donald Trump is set to visit the state on Saturday to meet with victims of the wildfires, the deadliest and most destructive in the state's history.

Many of the victims and the hundreds missing in the Camp Fire were elderly people who lived in the Butte County town of Paradise, in the foothills of the Sierra Nevada mountains. It is believed they were unable to flee the fast-moving blaze or were trapped in their cars as they attempted to escape.

Mr Honea said the number of those missing was likely to fluctuate as people call in to report loved ones unaccounted for or found alive.

"If you look at that list and see your name, or the name of a friend or loved one, please call to let us know," he said.

Investigators on Thursday collected DNA samples from relatives to help identify victims as hundreds of rescue personel and sniffer dogs worked to locate more victims.

Authorities said a wanted felon was killed inside the evacuation zone on Thursday following a high-speed chase with police. The man was wanted for a double homicide in 2014 and had been seen for three days camped out in his car.

"This is so devastating that I don't really have the words to describe it," Mr Brown said. "It looks like a war zone."

Authorities said it was unclear when residents would be allowed back into the town.

While the cause of the Camp Fire is still under investigation, a lawsuit has been filed against the local power company, PG&E, by fire victims claiming negligence by the utility.

The complaint alleged that the fire began on November 8 when a high voltage transmission line failed, igniting tinder-dry vegetation.

The utility was found to be responsible for several devastating fires in northern California last autumn that killed at least 15 people, and it faces billions of dollars in liability for the latest wildfires.